(1) Field of the Invention
The present invention relates to a one-packed epoxy resin composition. Epoxy resins in general can be converted into cured matters having excellent mechanical and electrical properties by heating and curing them. They have therefore have been widely used for various molding materials, composite materials, adhesives, etc., An object of the present invention is to provide epoxy resin compositions which have good compatibility with epoxy resins, exhibit excellent stability during storage, can be used at about room temperature over a long period of time and can be rapidly cured at a relatively low temperature upon heating.
(2) Description of the Related Art
As hardeners of epoxy resins, acid anhydrides, boron trifluoride amine complexes or amine compounds, etc. have been generally used. However, hardeners having a relatively high curing temperature such as acid anhydrides or boron trifluoride amine complexes involve drawbacks that they require molding at high temperatures over long periods of time while they have excellent stability during storage. Further boron trifluoride amine complexes involve drawbacks that they are readily inactivated due to their hygroscopic property and tend to affect the efficiency of the hardened product.
On the other hand, hardeners having a relatively rapid hardening rate such as amine compounds can not only provide a shortened period of hardening time for molding but also reduce energy costs due to lowering the hardening temperature and costs of auxiliary materials so that they are greatly advantageous and very valuable from a practical standpoint. However, the amine compounds encounter the problem that the time period over which they are useable as molding materials at about room temperature becomes markedly short and their moldability change in a short period of time so that they are unstable in operability. Furthermore, the amine compounds have a toxic problem in general and cannot be used widely.